Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/36—Sulfur-, selenium-, or tellurium-containing compounds
  • C08K5/37—Thiols
  • C08K5/375—Thiols containing six-membered aromatic rings

Definitions

• This invention generally relates to antioxidant compositions, and more particularly, to compositions especially suited for use with irradiated polyolefins and highly filled plastics, such as fire-retardant plastics.
• Olefin polymers are particularly subject to severe deterioration from the oxidative action of air at elevated temperatures. They are also vulnerable to degradation by the action of ionizing radiation when large amounts of such radiation are deposited onto the polymer, e.g., amounts of 5 ⁇ 10 10 ergs per gram and higher. Oxidative deterioration at elevated temperatures, i.e., temperatures above 50° C., is manifested by surface crazing, cracking, and ultimately complete embrittlement.
• a highly efficient antioxidant system is particularly desirable for irradiated plastics. Often, during irradiation, much of the antioxidant is consumed or rendered incapable of functioning as an antioxidant. It is therefore necessary that an antioxidant system be employed for plastics which are to be irradiated which will be effective and survive radiation when used in small quantities so as to prevent oxidation even after being subjected to irradiation.
• An antioxidant composition especially suited for irradiated or fire-retardant plastics, comprising a hydroxy aromatic compound containing sulfur and an organic phosphonate compound.
• the hydroxy aromatic compound generally comprises phenol, cresol and naphthol groups with the sulfur preferably attached to at least one cyclic unsaturated compound.
• the cyclic unsaturated compound is a homoaromatic unsaturated ring compound wherein a ring carbon atom is attached to the sulfur.
• Suitable phosphonate compounds have the formula ##STR1## wherein R, R' and R", any two or all three of which may be the same or different, and which may contain further phosphonic moieties, each represents a substituted or unsubstituted alkyl, alkenyl, aryl, alkylaryl or heteroaromatic (e.g., a triazine) radical, or a polymeric radical, or R has the meaning above and R' and/or R" represent a hydrogen atom or are linked together to form a ring.
• R' and R" are preferably non-aromatic, e.g., are alkyl and alkenyl groups, especially vinyl and allyl groups, because aromatic substituents have a greater tendency to be hydrolysed.
• the present invention provides an antioxidant composition comprising a mixture of (a) a non-metallic hydroxy aromatic compound containing at least one sulfur atom attached to an unsaturated carbocyclic group, and (b) an organic phosphonic acid or a diester or monoester thereof.
• the present invention also provides a polymer composition comprising one or more polymers which are susceptible to oxidation and an antioxidant composition as defined above.
• the present invention is based on the surprising discovery that a blend of compounds (a) and (b) above exhibits better antioxidant properties than either compound used alone at the same total additive level.
• the antioxidants of the present invention have the further advantage of being very efficient at elevated temperatures.
• antioxidant compositions of this invention are particularly useful in plastics which are to be irradiated.
• the antioxidant composition of this invention has also been found well suited for use in highly filled fire-retardant plastic compositions.
• antioxidant compositions of the present invention can be employed in small amounts, e.g., amounts of from 1 to 6%, in irradiated plastics compositions especially irradiated cross-linked olefin polymers, without substantially impairing either their antioxidant efficiency or the degree of the cross-linking of the material under irradiation.
• the present invention further provides a polymer composition comprising at least one irradiated cross-linked polymer and an antioxidant composition comprising (a) a hydroxy aromatic compound containing at least one sulfur atom and (b) an organic phosphonic acid or a diester or monoester thereof.
• the hydroxy aromatic compound (a) is preferably non-metallic and the sulfur atom is preferably attached to an unsaturated carbocyclic, e.g., homoaromatic group, such as a phenol, cresol or naphthol group, but the irradiated cross-linked polymer compositions of the present invention may include antioxidant compositions in which compound (a) contains a sulphur atom attached to a carbon atom in a heteronuclear unsaturated ring, e.g., a triazine ring as in 6-(4-hydroxy-3,5-t-butylanilino)2,4-bis(n-octylthio)1,3,5-triazine.
• an unsaturated carbocyclic e.g., homoaromatic group, such as a phenol, cresol or naphthol group
• antioxidant compositions in which compound (a) contains a sulphur atom attached to a carbon atom in a heteronuclear unsaturated
• hydroxy aromatic compounds have the formula R 1 --S--R 2 wherein R 1 and R 2 , which may be the same or different, each representing a substituted or unsubstituted phenol, cresol or naphthol groups.
• R 1 and R 2 which may be the same or different, each representing a substituted or unsubstituted phenol, cresol or naphthol groups.
• R 1 and R 2 which may be the same or different, each representing a substituted or unsubstituted phenol, cresol or naphthol groups.
• R 1 and R 2 which may be the same or different, each representing a substituted or unsubstituted phenol, cresol or naphthol groups.
• R 1 and R 2 which may be the same or different, each representing a substituted or unsubstituted phenol, cresol or naphthol groups.
• R 1 and R 2 which may be the same or different, each representing a substituted or unsubstituted phenol, cresol or napht
• Diesters of the hereinbefore mentioned organic phosphonic acid are especially preferred and amongst such compounds there may especially be mentioned, for example, diesters of 3-t-butyl-4-hydroxy-5-methyl benzyl phosphonic acid, amyl phosphonic acid, allyl phosphonic acid and ⁇ -ethyl-3,5-di-t-butyl-4-hydroxybenzyl phosphonic acid.
• diesters of 3-t-butyl-4-hydroxy-5-methyl benzyl phosphonic acid amyl phosphonic acid, allyl phosphonic acid and ⁇ -ethyl-3,5-di-t-butyl-4-hydroxybenzyl phosphonic acid.
• These include, for example, di-n-octadecyl(3-t-butyl-4-hydroxy-5-methylbenzyl) phosphonate, diallyl allylphosphonate and diamylamylphosphonate.
• free phosphonic acids may also be employed.
• Suitable phosphonates are 2,4,6-tris(dialkyl or dialkenyl phosphonato)1,3,5-triazines, e.g., 2,4,6-tris(diallyl phosphonato)-1,3,5-triazine, and the phosphonate of the formula ##STR2##
• thermoplastic olefin polymers such as polyethylene, polypropylene, ethylene/vinylacetate copolymers, ethylene/acrylic ester copolymers, ethylene/propylene copolymers and ethylene/propylene/diene terpolymers.
• Antioxidant compositions of the invention are also suitable for use with other polymers which are sensitive to oxidation including polyvinylchloride, polyvinylidenechloride, polyvinylidene fluoride, chlorinated polyethylene, acrylics, saturated and unsaturated olefin elastomers, polyethers and polyesters.
• the present invention also provides shaped articles made from the polymer compositions, especially heat-recoverable articles made from the irradiated cross-linked polymers.
• antioxidant composition is a mixture of compounds (a) and (b) as defined above a single compound containing both an organic phosphonate radical and a radical containing a hydroxy aromatic group and a sulfur atom could also be expected to be effective.
• antioxidants were blended with a high density polyethylene (Marlex 6003, Philips Petroleum Company, density 0.096, M. I. 0.2) on a mill at 160° C. and hydraulically pressed into 6 in by 6 in by 0.020 in slabs at 170° C. and cooled, then irradiated to a dose of 20 Mrads.
• a high density polyethylene Marlex 6003, Philips Petroleum Company, density 0.096, M. I. 0.2
• the number of days of heat aging which resulted in rupture of the sample at or below 150% elongation on the Instron was selected as the time to failure.
• the phosphonate alone (antioxidant A) or the hydroxy aromatic compound containing sulfur alone generally failed in less than 13 days at the 3 pph level.
• a 3 pph level of a blend of phosphonates and hydroxy aromatic compound containing sulfur gave substantially better results in the order of 25 days, indicating a synergestic result from the blending of the two ingredients.
• a non-sulfur containing phenol (antioxidant C) and a phenol with the sulfur atom not attached to an aromatic group (antioxidant I) were evaluated, little or no increased life was obtained.
• the sulfur atom is attached to an unsaturated heterocyclic compound such as a triazine ring (F)
• an unsaturated heterocyclic compound such as a triazine ring (F)
• the preferred system is a phosphonate with a hydroxy aromatic compound containing sulfur which has at least one of the sulfur atoms attached to an aromatic ring.
• Stauffer E719 from the Stauffer Chemical Company having the formula ##STR3## was blended with antioxidant E of Table I and Marlex 6003. Failure was measured as generally described in Example I but the temperature of heat aging was 200° C. and failure was defined as an elongation at or below 50%.
• a fire retardant plastic of the following formula was used to evaluate antioxidant efficiency.
• Example IV The experiments of Example IV were generally repeated using diallylallyphosphonate in place of di-n-octadecyl-3-t-butyl-4-hydroxy-5-methylbenzyl phosphonate with similar results.
• Example IV The experiments of Example IV were generally repeated using diamylamylphosphonate in place of di-n-octadecyl-3-t-butyl-4-hydroxy-5-methylbenzyl phosphonate with similar results.

Landscapes

• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Anti-Oxidant Or Stabilizer Compositions (AREA)

Priority Applications (1)

Applications Claiming Priority (1)

Related Parent Applications (1)

Related Child Applications (1)

Publications (1)

Family

ID=23604166

Family Applications (1)

Country Status (8)

Cited By (4)

Families Citing this family (2)

Citations (11)

Family Cites Families (8)

• 1974
  • 1974-10-10 US US05/513,864 patent/US4148747A/en not_active Expired - Lifetime
  • 1974-10-10 DE DE19742448415 patent/DE2448415A1/de not_active Ceased
  • 1974-10-11 JP JP49117003A patent/JPS5925816B2/ja not_active Expired
  • 1974-10-11 CA CA211,232A patent/CA1061998A/fr not_active Expired
  • 1974-10-11 GB GB23125/77A patent/GB1490074A/en not_active Expired
  • 1974-10-11 GB GB25832/77A patent/GB1490075A/en not_active Expired
  • 1974-10-11 GB GB44269/74A patent/GB1490073A/en not_active Expired
  • 1974-10-11 IT IT28353/74A patent/IT1027580B/it active
  • 1974-10-11 FR FR7434258A patent/FR2247500B1/fr not_active Expired
  • 1974-10-11 BE BE149473A patent/BE821001A/fr not_active IP Right Cessation

Patent Citations (14)

Also Published As

Similar Documents